|iii) Where do we have to go to see the Leonids?
There are a number of factors to take into account when it comes to deciding
on a location.
First, take a look at these peak times on the night of the 18th and morning
of the 19th. Is the Leonid radiant above your horizon at those times? Maybe not.
If not, you won't see many of those meteors.
When the radiant is just below your horizon, or just above, you will see 'earthgrazers'
- nice long Leonids coming up from the horizon. In a posting to the MeteorObs
email list on September 16th, meteor researcher Pete Gural wrote, "...
using a meteor simulation analysis one can show that to observe grazers that
reach above 30 degrees elevation, the radiant must be between 2 degrees below
the horizon to 3 degrees above the horizon... for northern latitudes the
duration is roughly one-half hour but at the equator this can last for up to 40
If you have a sky program on your computer, dial up November 18th and 19th,
and see when the sickle of Leo rises over your local horizon. You can also check
out what time the sickle of Leo will rise by adjusting the date and your local
time on the 'Whole Sky Chart' on the Heavens Above website, at http://www.heavens-above.com
Basically, observers in Europe will see the first big peak well, and
observers in the Americas may see nice long 'earthgrazer' meteors from that
peak, around 11.00 pm EST on November 18th. The second big peak will favor the
Americas, around 5.30 am EST on the morning of November 19th.
What hours do you have in darkness from the location where you live? What
time does twilight end and start? Check these times against the predicted peak
times for the various rev trails. You might want to travel to get more hours of
darkness centered on the time of maximum activity! This can be especially
crucial if the peak time is shifted a bit from predictions. You might want to
give yourself a bit more 'time zone safety'. Get your times of twilight from the
U.S. Naval Observatory site at http://aa.usno.navy.mil/data/docs/RS_OneDay.html
Apart from radiant height and hours of darkness, what factors should we
consider for location?
Cloud cover. If you live in an area that is always cloudy and/or rainy or
snowy in November, get out. Go somewhere that has a higher percentage of clear
skies in mid-November. To see a global map of mean November cloud cover at night
(from 18 years of satellite data), check out Jay Anderson's site at http://home.cc.umanitoba.ca/~jander/Leonids/leonids.ht
Elevation. November can bring heavy fog when the temperature drops at
night. Get as high as you can above ground level. Check out your topographical
maps, or take a look at some online relief maps. For the U.S., check out the
U.S. Color Landform Atlas at: http://fermi.jhuapl.edu/states/states.html
For Canada, check out the following address for a great interactive zoom-in
relief map: http://www.geoaccess.ca/site/english/maps/reference/national/
choose Reference Maps - National - Relief (Interactive).
Humidity. Humid air - and not just ground fog - may also hamper
observations this year. Because there will be a full moon, the humidity in the
air will tend to dissipate the light, and make your viewing more washed out. If
you can, try to get to a dryer area to observe.
Aurora. No, we're not kidding. Those of us in northern latitudes have
been fortunate to see a lot of aurora lately. However spectacular these may be,
we don't want a bright aurora with a full moon as well on the Leonid maximum.
Watch the aurora site at http://www.spacew.com/www.aurora.html
to see if you
should consider traveling further south.
Those are the main location factors. Temperature is secondary - but November
is winter, and if you can't take the cold, go south to observe if you can afford
Stay mobile - be prepared to relocate at the last moment if you need to
escape cloud, fog or other factors that may impede your view of the Leonid
meteor storm. Consider mobility now. Check out friends or astronomy contacts in
various locations, to give you some observers to hook up with if headed to a
strange location. Make a list now of contacts and observing locations - say 4-5
hours north, south, east, and west of you in driving time - and another list say
a 9-10 hour drive in each direction. Pack your car and be prepared to move. Get
your identification and customs slips ready to go in case you have to cross a
border. A good list of astronomy clubs can be found on the Sky and Telescope
website at http://skyandtelescope.com/resources/organizations/
If you cannot travel, and just want to link up with a group of local
observers and take your chances on the weather, this Sky and Telescope link will
also give you details on the club closest to you!
In spite of the full moon brightening the sky though, it is still very
important to try to get out of the city. Bright glaring streetlights will blind
you to many of the meteors falling in the sky! Man-made light pollution still
destroys our night sky.
Bookmark the following weather websites for reference, and watch them
carefully in the days leading up to the Leonids:
Maps of where clear skies are now, and in 24 hours time, in North America: http://www.cmc.ec.gc.ca/cmc/htmls/clds_vis_e.html
and also http://www.intellicast.com
- choose Stargaze, then Viewing Conditions.
Map of the predicted travel weather in 1/2/3/4/5 days time: http://www.intellicast.com
and choose Travel.
Also check out Canadian observer Attilla Danko's 'Clear Sky Clocks' for
astronomical viewing conditions at locations across North America. You can pick
a location, check it out, then ask to see conditions at sites within 60 miles,
or 120 miles - an extremely useful tool! http://www.cleardarksky.com/csk/
Links to Leonids Web Sites
Peak Online Estimator: If you want to find out the estimated peak times for where you live, go to this site, and check out your location. At the bottom of the screen is a flux calculator. Pick the city closest to you and launch the calculator. It should give you a pretty good idea what the times will be for your area.